Superb martial artist
Fully trained onna bugeisha warrior
Soultaker sword grants:
Ability to capture the soul of every being it kills and communicate with that soul, including that of her deceased husband

In February 2013, Katana received her own series written by Ann Nocenti and with art by Alex Sanchez. This book is considered by DC as part of the "Fourth Wave" of New 52 titles.[2]Katana lasted for ten issues. The final issue was released on December 11, 2013.[3]

Tatsu Yamashiro(山城 たつ?) was an average Japanese girl, save for her proficiency in the martial arts, a trait encouraged by her parents.[4] Two brothers—Maseo and Takeo Yamashiro—both proclaimed their love for her. While she liked both, she chose Maseo as her husband. Takeo "did not take this well" and refused to attend the couple's wedding.[4] Maseo disowned his brother, who had joined the Yakuza and taken their mark of a large dragon tattoo across his chest. Tatsu and Maseo, mourning the deaths of Tatsu's parents, started a family of their own. Tatsu gave birth to twins, Yuki and Reiko. Meanwhile, Takeo rose through the Yakuza's ranks and indulged his "exotic tastes" for ancient weapons.[4] He was presented with a pair of matching swords by General Karnz (later henchman to Baron Bedlam), one of which Takeo favored for its mystical properties.

Takeo spent days preparing himself, before taking both swords to the Yamashiro residence, demanding his brother duel for the "prize" of Tatsu.[4] During the course of the struggle, a fire was started, and—while Maseo was distracted by his children—Takeo killed his brother with the sword which would become known as "Soultaker". Tatsu arose just in time to see her husband die and engaged Takeo, gaining the upper hand and disarming him. Attempting to save her children, she heard her husband's voice coming from the sword, telling her they were already lost. Escaping with her life, Tatsu began training as a samurai under a master called Tadashi. After much time she graduated from his tutorship and left for America where she intended to use her talents to fight for justice. She took the codename Katana after the sword that she wielded, possessed for some time by the soul of her husband.[4][5]

Eventually Tatsu journeyed to Markovia, a small Baltic state, where she had tracked down Karnz, and she was successful in killing him, inadvertently implicating Black Lightning (coincidentally there with Batman) in her crime.[6] Attempting to rectify the misunderstanding by freeing Black Lightning, she encountered a young girl who was named Halo.[7] The two joined up to rescue Black Lightning, Batman (himself captured due to a blunder by Halo), and Bruce Wayne's employee Lucius Fox from their captor, Baron Bedlam.[7]

Batman was himself in Markovia to rescue Lucius Fox, and having sought—and failed to gain—the help of the Justice League of America, had resigned his membership in the Justice League. Inspired by the teamwork he encountered between Black Lightning, Katana, Halo, Geo-Force (Prince Brion of Markovia), and Metamorpho (also coincidentally present), Batman decided to form the Outsiders.[8] The team managed to end the Baron's tyranny in Markovia and moved to Gotham City, where they set up their headquarters (a former penthouse of Bruce Wayne, secretly the Batman). Tatsu became Halo's guardian and the two moved into the penthouse.

At the same time, Takeo was still at large and had followed Tatsu to Gotham City. Secretly he switched swords with her and left for Tokyo with the Outsiders on his tail. Takeo took the sword to his master, the godfather of the Yakuza, known only as the Oyabun. Performing a specific ritual, the Oyabun and Takeo managed to recall the souls that inhabited the sword, who proceeded to take corporeal form.[9] Among them were legendary mercenaries and assassins, but also Maseo, who was now a slave to the Oyabun. Katana—and the Outsiders—had to fight them all, but was ultimately able to reclaim the Soultaker from Maseo. Forced to kill her husband, she was also able to kill Takeo, finally putting some of her ghosts to rest. By undoing the ritual however, her husband returned into the sword as well.

At one point the Outsiders split from Batman's leadership and took up residence in Markovia where they were funded by the Markovian crown (Geo-Force is a prince of the royal family). They became the official agents of Markovia and moved to the city of Los Angeles where they made their headquarters in the Markovian embassy, while retaining another secret HQ just off the shore. Although Tatsu had left her past behind, the Oyabun returned in her life and sent a tengu after her, with which he captured her. Her teammates in the Outsiders, namely Halo and Looker were able to save her using other tengu and the tengu leader, who aided them in battle.[10][11]

After a while, the team disbanded after various tragic events surrounding Geo-Force's parents and Markovia. Nonetheless the Outsiders were forced to defend Markovia against the Manhunters, but during the fight Halo was knocked into a coma, saving Katana's life. Bounded by giri-ninjo (a debt of honor even unto death), Tatsu left the team so she could tend to Halo's wounds. During that time however, she was approached by a family member of her husband, who wished her to accompany the Suicide Squad on a mission to destroy a large hoard of weapons that was about to be sold to the Yakuza. She declined on the basis of her giri-ninjo, although she was willing to help if the need was truly desperate. That family member was later killed, and she went after the killer, the Daichi-Doku's Oyabun (of which her relative was a member), who did not wish to see the weapons destroyed and tried to stop the Suicide Squad. During that adventure, she saved the life of Bronze Tiger and Manhunter (Mark Shaw), making them honor-bound to her by giri-ninjo. Mark Shaw then assisted her in taking down the Daichi-Doku's Oyabun. The Oyabun committed ritual suicide and Katana stood by as his "second", ready to help with a blade strike so he could keep his honor.

Eventually though the Outsiders re-form and return to Markovia. Instead of a peaceful reunion however, the team become trapped in a web of public relations that brands them outlaws. Although the charges would be dropped eventually, the team was fractured. Halo dies from an assassin's blast but was reborn in a new body, which put an immense strain on Tatsu's relationship with Halo. Katana joins a team with Geo-Force and Technocrat, taking the lead. She develops a mild romantic relationship with Joey Hong, an Asian associate of Guy Gardner.[12] During a lone mission, Tadashi, her old mentor sends Lady Shiva to claim Katana's Soultaker sword. Shiva confronts Katana, who had been battling a gang of drug dealers. Katana had slain many, but refuses to kill the youngest member, something Shiva insults her for. Shiva, being world-renowned as the world's greatest assassin and fighter, was able to kill Katana with her own sword. Katana returns to life after a trial by combat within her sword, which includes confronting many of the souls of the people she had killed. Afterwards, she manages to find her old mentor and take his life. The two splinter teams would eventually reunite, to take on more supernatural threats focused around the new team member Sebastian Faust. Katana and her friends suffer through the mental and physical tortures that Faust's father, Felix, puts them through. Halo eventually frees them by destroying several of Felix's items of power. Soon after, the group breaks apart. After disbanding, Tatsu has kept her association with her old allies among the Outsiders (such as Black Lightning, Geo-Force, and Halo), and although they did not operate as an official team, were always seen alongside each other during major crises. Her close ties to Batman also saw her fighting by his side, several times, notably during the Imperiex crisis and the Day of Judgment incident when Hell invades Earth. The main battle against the villain, the rogue angel Asmodel, with the power of the Spectre, takes place in New York. Katana personally protects Madame Xanadu who is guarding the rest of Asmodel's power with a mystical shield. Katana's protection of Xanadu is assisted by Doctor Occult, Phantom Stranger, and Alan Scott. Later, Katana assists Batman when he and Superman were declared outlaws. Katana was also called upon by Black Canary, together with other female mercenaries, in order to rescue Oracle from Senator Pullman. After Oracle was saved, Katana received a card, together with the promise of a favor if required. Katana later returns to assist Oracle in issue #108 alongside dozens of other agents.

Later Katana joined a new team of Outsiders after assisting them in defeating a more powerful Sabbac. That team consisted of all new members, with the exception of Metamorpho who rejoined the team after Shift's demise. In Outsiders #42, Katana dons a new costume, as she felt it inappropriate to wear a costume based on Japan's flag, since the country had revoked her citizenship due to her membership with the controversial team. Later, Katana summons Sabbac to destroy Dr. Sivana's base with his Hellfire. Katana remains an active member of the Outsiders following the One Year Later continuity jump. Initially, the team is led by Nightwing, but later leadership transfers to Batman. Batman decides to 'test' Katana and the rest of the initial team, in order to design a better team. Katana is Batman's first official recruit.

While escorting Killer Croc to incarceration, the Outsiders' vehicle is demolished by Maseo, Yuki, and Reiko, who have all been revived as Black Lanterns. Katana, believing that she has been reunited with her lost family, lets her guard down, but is saved from death by her teammates. Realising the truth, she draws her sword, preparing to fight her undead husband.[13] When Katana stabs Maseo, Soultaker reveals to her the Black Lanterns' full intentions. Her attacks soon prove to be completely ineffectual against Maseo, who is instead destroyed by an outpouring of light from Halo, who also destroyed Katana's undead children.[14]

The events of Flashpoint led to reboot in continuity for the DC Universe which altered some of the fictional history but left other pieces in place. Each of the DC Universe titles were relaunched and the rebooted titles have been labeled The New 52. In this rebooted continuity, a newly healed Barbara Gordon returns to the Batgirl identity and takes a leave of absence from the Birds of Prey[15] and suggests that Katana take her place full-time on the team.

Katana joins Black Canary and Starling as the third member of the Birds of Prey. Katana is described as a lethal fighter who has spent the last year waging war on the Yakuza clan that is responsible for the death of her husband. She is rumored to be mentally unstable due to her belief that her husband's soul, whom she often converses with in Japanese, resides in her sword.[16]

After a number of adventures with the Birds of Prey, Katana leaves the group in order to keep an eye on a cult of assassins known as the Daggers.[17] She later accepts membership in Amanda Waller's new Justice League of America in exchange for information on her husband's murderers.[18] When DC launched Justice League of America, they also launched the solo series Katana, focusing on Tatsu's abiding mission to track down her husband's killer. The series lasted 10 issues. After this, Katana made an appearance in Green Arrow #27 (2014), where she is told by the mysterious blind man Magus that the death of her husband relates to the Outsiders, the society formed of various weapon clans and connected to Green Arrow's new origin story. The Soultaker is worked into the Green Arrow mythology as the totem of the Sword Clan, which has parallels in the Fist, Mask, Shield, Axe, Arrow, and Spear Clans. Representatives from each of these clans make up the Outsiders, a secret society dedicated towards ending global corruption, but which is itself largely corrupt. Katana joins the Outsiders. In Green Arrow: Futures End #1 (2014), set five years later in one possible future, Tatsu is shown to still be a member of the Outsiders, which has developed a grudging relationship with Green Arrow, who rejected leadership of the Arrow Clan in the main Green Arrow series five years before.

Katana is a highly proficient hand-to-hand combatant and swordswoman, having studied martial arts as a child and later being trained by the samurai Tadashi. From her time with the Outsiders and Batman, she has also developed strong tactical skills.

Katana's Soultaker sword, along with its non-powered twin, was forged in the 14th century by Muramasa, whose swords were said to be cursed and make those who were evil commit evil acts. It sometimes takes the souls of those it kills, storing them inside the sword, where they can engage in limited communication with whoever wields it. These souls can be reincarnated by the means of a sacred ritual, under which they serve their summoner, even if it is against their will. In The New 52, the Soultaker is established as being the 'Sword Totem' of the Outsiders, meaning like the other totems it supposedly bestows immortality and enlightenment upon its wielder, although some like Green Arrow are sceptical of the literal truths of these claims.

In addition to the Soultaker, Katana often carries additional weaponry into battle.

Katana appears in the Batman: The Brave and the Bold, voiced by Vyvan Pham, and later by Kim Mai Guest. In the episode "Enter the Outsiders!", she is shown as a member of the Outsiders alongside Black Lightning and Metamorpho, as teenagers rather new to their abilities. They serve the sewer-dwelling villain Slug until Batman and Wildcat defeat him and persuade them not to follow Slug's ways. Katana was mostly silent, typically letting her actions speak for her. In "Inside the Outsiders!", a different origin is explored via a nightmare created by Psycho-Pirate: Katana was the student of Tadashi, who was killed by the evil samurai Takeo. Psycho-Pirate makes her believe that it was her talkative nature that led Takeo to Tadashi, and she becomes silent out of shame. Batman reminds her that this was not what happened; Tadashi sacrificed himself to make her a greater warrior, and her silence honors his teachings of self-control. In the teaser of the episode "Requiem for a Scarlet Speedster!", she and the other Outsiders fight and defeat Kobra with the aid of two new members: Geo-Force and Halo.

Katana appears as one of the lead characters in Beware the Batman,[20] voiced by Sumalee Montano.[21] Tatsu Yamashiro is portrayed as a CIA agent who infiltrated the League of Assassins, then faked her death in order to remove the Soultaker sword from their possession. Alfred Pennyworth was a friend of her father during their MI-6 days, and later became Tatsu's godfather. Tatsu agrees to serve as Bruce Wayne's bodyguard while Alfred is recovering from injuries. In "Safe", she is guarding Dr. Jason Burr when she is confronted by Silver Monkey, who reports her survival to Lady Shiva.[22] In "Family", Tatsu confesses to Bruce that she has acquired the Soultaker sword and hidden it on the estate. Alfred vouches for her reliability, but Bruce demands their resignations. Bethanie Ravenscroft and Silver Monkey capture Wayne and demand the Soultaker as ransom. With Alfred's assistance, Tatsu rescues Wayne and then fights the League's ninjas by Batman's side. Tatsu learns that Batman is Bruce Wayne and that she passed her "final test" to become his partner. In "Allies", she takes the codename "Katana", which was also her codename in the League of Assassins. In "Fall", a flashback reveals that Ra's al Ghul encountered MI6 Agents Alfred Pennyworth and Edogawa Yamashiro (the father of Katana) in the past, with Edogawa forced to betray Alfred to Ra's in their last encounter under threat of his family. Ra's ordered Edogawa to use the Soultaker sword on Alfred, but Alfred fought back, causing the powers of the sword to activate, leading to Edogawa's death. In the present, Batman and Katana arrive to stop Ra's al Ghul. Katana and Alfred barely escape from the League of Assassins with Ra's al Ghul commenting on how Alfred killed Edogawa. In "Darkness", Ra's al Ghul has Alfred and Katana captured when they try to break into his lair. In "Reckoning", Ra's al Ghul manipulates Katana into killing Alfred to avenge the death of her father. She refuses, which nearly results in having Ra's al Ghul kill them all, only for Tobias Whale to arrive with a captured Batman.

Rila Fukushima portrays Tatsu Yamashiro/Katana on The CW series Arrow.[23][24] Actress Devon Aoki was originally cast in the role but was forced to drop out due to a scheduling conflict.[25][26] Tatsu Yamashiro is first introduced in the third season premiere, "The Calm", in flashbacks to a time when Oliver Queen was recruited as a mercenary for Amanda Waller operating out of Hong Kong. Through his handler, Maseo, he got to know Maseo's wife Tatsu and son Akio. Like her husband, Tatsu is a brilliant Japanese warrior; she expertly wields a katana which has been in her family for generations. Over the course of the season, Oliver and Maseo's work for Amanda Waller runs them afoul of gangster China White and U.S. General Matthew Shrieve. When the latter unleashes a deadly bioweapon in Hong Kong, Oliver and the Yamashiros fail to stop him, and Akio is killed. In the present day narrative, it is revealed that Maseo then joined the League of Assassins and parted from Tatsu, becoming a loyal lieutenant of Ra's al Ghul, taking the name Sarab. He initially helps Oliver survive a deadly injury from Ra's by taking him to Tatsu for healing, but Ra's later reminds him of his need for loyalty. When Oliver's friends lead an assault on Ra's towards the end of the season, Tatsu accompanies them, in her trademark costume from the comics. She and Maseo fight; Maseo rejects an attempt at redemption, and Tatsu is forced to kill him. In fourth season episode "Unchained" she is revealed to be a member of the Crescent Order which guards the Lotus, a potion created to counter the effects of the League of Assassins' Lazarus Pit.

In the second season episode of Legends of Tomorrow, "Shogun", the crew of the Waverider travel to Feudal Japan to rescue Citizen Steel and Atom. An injured Nate is tended to by woman called Masako Yamashiro. It is revealed that Masako's father, Ichiro, forged the finest blade and armour in Japan for his son. His son was ordered to commit suicide by a ruthless Shogun, an order he accepted to retain his family's honour, it was then ordered that the blade be destroyed. Ichiro hid the blade and later gave it to Ray Palmer so that he could use it to fight the Shogun. Once the Shogun had been defeated, Nate passes the blade to Masako and it is implied that she would become the first woman to defend her village as Katana and eventually the blade and identity would pass down to her descendant Tatsu.